Flexible multiconductor heater



April 29, 1969 p. HYNES I 3,441,712

FLEXIBLE MULT I CONDUCTOR HEATER Filed Oct. 25; 1967 INVENTOR. Leefi/gizeo" ATTORNEY,

CYLINDER 4 RETRAC I 5/ 4 ADVANCED April 9, 1969 L. P. HYNES 3,441,712

FLEXIBLE MULTICONDUCTOR HEATER I Filed Oct. 23, 1967 Sheet 2 of s '72 Z5 j 1 11- 2 Z g g:

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Y afii uwau scam ATTORNEYS United States Patent 3,441,712 FLEXIBLEMULTICONDUCTOR HEATER Lee P. Hynes, Haddoniield, N.J., assignor to HynesElectric Heating Company, Kenilworth, N.J., a corporation of New JerseyFiled Oct. 23, 1967, Ser. No. 677,149 Int. Cl. Hb 3/06 US. Cl. 219-539 3Claims ABSTRACT OF THE DISCLOSURE The present invention relates to amultiresistor flexible electric heater which is adapted to fit in ahose, conduit, or pipe.

A purpose of the invention is to give flexibility to an electric heaterin all directions to facilitate bending ac cording to the shape of ahose, conduit or pipe.

A further purpose is to aid in replacing broken insulators withoutdisassembling an entire electric heater.

A further purpose is to grip the resistors between tongues of three ormore insulator segments, so that a band holding together the insulatorsegments will also apply gripping pressure on the resistors.

A further purpose is to grip the resistors between insulator segmentsand an insulator core.

A further purpose is to cross-connect between resistors within radialslots of an end insulator.

A further purpose is to permit automatic or semiautomatic assembling ofthe insulator segments at intervals along an electric heater.

A further purpose is to assemble the insulator segments in a jig.

Further purposes appear in the specification and in the claims.

In the drawings I have chosen to illustrate a few only of the numerousembodiments in which the invention may appear, selecting the forms shownfrom the standpoints of convenience in illustration, satisfactoryoperation and clear demonstration of the principles involved.

FIGURE 1 is a diagrammatic top plan view showing the chuck and thewelding means for causing the insulator segments to grip the resistorspreparator to joining a band surrounding the insulator segments.

FIGURE 2 is a view similar to FIGURE 1 with the chuck closed and thewelding elements in the process of completing a weld.

FIGURE 3 is a view similar to FIGURE 2 showing the insulator afterbending back the outwardly extending ends of the band.

FIGURE 3a is a face view of the tongue and the gripping recess of one ofthe insulators.

FIGURE 3b is a view corresponding to FIGURE 3 showing a modifiedconstruction of one of the insulators in which the gripping surfacesextend clear across.

FIGURE 3c is a view similar to FIGURE 3 showing a die makingindentations on the band to tighten the band.

FIGURE 4 is a section on the line 44 of FIGURE 3.

FIGURE 5 is a diagrammatic side elevation showing one position of thechuck.

FIGURE 6 is a diagrammatic side elevation showing the mechanism foradvancing and retracting the chuck.

FIGURE 7 is a cycle diagram showing the operation of any suitablecontrols such as valves for the advance cylinders and the chuckcylinders.

FIGURE 8 is a top plan view of a jig for assembling insulator segments.

FIGURE 9 is a section on the line 9-9 of FIGURE 8.

FIGURE 10 is a view similar to FIGURE 9 showing the lowermost resistorsin place.

FIGURE 11 is a section on the line 11-11 of FIG- URE 8.

FIGURE 12 is a section on the line 12-12 of FIG- URE 8.

FIGURE 13 is a transverse sectional view showing an assembly ofinsulator portions for an electric heater having six resistors.

FIGURE 13a is a view similar to FIGURE 13 showing a modified form of theinsulator of the invention.

FIGURE 14 is a partially sectional fragmentary side elevation of the endportion of an electric heater showing one way for insulating thejumpers.

FIGURE 15 is a right end elevation of FIGURE 14.

FIGURE 16 is a view similar to FIGURE 14, showing a different form ofinsulation for the jumpers at the end.

My US. Patent 3,286,078 illustrates in FIGURE 7 a form of separableinsulator for use with two electric resistors in an electric heater.This form gives considerable flexibility but is limited in the sharpnessof bends which are permissible.

My U.S. Patent 2,963,539 shows an electric heater which is flexible incertain directions but not flexible in one particular direction.

The present invention is concerned with an electric heater of greatlyimproved flexibility, which is suited particularly for inclusion in ahose, conduit or pipe, and which is adaptable where three or moreresistors are used.

There are several different reasons for using three or more resistors.One common reason is to make the circuit convenient for a multi-phasepower source, particularly a three-phase source.

Even on single-phase installations, however, there is a demand for aspare resistor which can be energized without disassembling the electricheater itself, merely by changing the connections at one end. Thisallows for the possibility that one resistor may be burned out orotherwise rendered inoperative.

In some types of service, also, it is desired to have more uniformdistribution of a source of heat around the hose or pipe, and this is afurther reason which favors the use of three or more resistors.

It will be evident that while the invention will serve for heaters whichare installed in rigid piping or the like, including piping having aspiral shape or sharp bends, it is also very effective for use withinflexible hose, for example, corrugated stainless steel hose or plastichose. Heated hoses of this type are desirable, for example, to heat tankcars and other containers to fluidize the contents, and to heat inletand discharge hoses.

The invention thus provides a very effective flexible heater havingthree or more resistors, and also facilitates replacement of insulatorsand portions of insulators which may break either during manufacture orin service. It is no longer necessary to string insulators from the endin order to replace them.

Considering first the form of FIGURES l to 7, I there show helicallywound electric resistor coils 20 of suitable electric resistance wire,for example Nichrome, Inconel, Monel, or otherwise, which haveflexibility or resilience laterally and are resilient radially and thuscan be contracted by gripping. Monel is an alloy containing nickel andcopper, the nickel being approximately twice the copper in weightpercent. Inconel is a nickel base alloy containing about 13% ofchromium, about 6% of iron and small amounts of manganese, silicon andcopper.

In the form under discussion, three insulator segments 21, preferably ofceramic or porcelain or other heat resisting insulating material(hereinafter called ceramic), have outer arcuate portions 22 which areintended to form part of a circular outside contour of the insulator,and also radially inwardly projecting tongue portions 23.

Each of the tongue portions at its sides has a longitudinally extendingrecess 24 which is adapted to engage and grip one of the sides of one ofthe coiled resistors At the middle of the arcuate portion 22 andextending around it is a recess 25 which is to receive a band such as astrap or wire holding together the insulator segments.

The arcuate portion of the insulator segments have at their forward andrear corners fillets 26 which are intended to protect against jambing onobstructions in the hose or pipe.

As best seen in FIGURE 1, jaws 27 of a chuck 28 sur round the insulatorsegments, and receive them within the curved inner portions of the jaws,along with a suitable sheet steel strap or band 30 in the recess 25. Inorder to prevent the segments from dropping through the chuck jaws 27,the jaws have at the bottom leaf spring metal fingers 31 which canretract out of the way when the jaw must move longitudinally withrespect to the insulator segments.

In the preferred embodiment each of the jaws 27 has over its inner facea rubber or elastomeric gripping surface 32 which is capable when thejaws are compressed of engaging not only the outside edges 33 of theinsulator segments but also the band so as to push it into huggingrelation as desired.

The electric resistors as shown in FIGURE 1 are equallycircumferentially positioned as at the corners of an equilateraltriangle, so that they are opposite the recesses 24.

FIGURE 2 shows pressure being applied to close the chuck jaws 27 asindicated by arrows 34, so that the walls of each of the recesses 24 onthe opposite sides of the tongues 23 engage and pinch the resistorcoils, contracting them slightly radially inwardly so that the coils areunable to slip longitudinally with respect to the resistors.

FIGURE 1 shows ends 35 of the band or strap 30 engaged by openelectrodes 36 of a spot welding mechanism and as shown in FIGURE 2. theelectrodes 36 close as indicated by arrows 37 and spot welding currentis passed through the electrodes so as to create a spot weld at 38uniting together the ends of the band 30.

It will be evident that other techniques for fastening the ends of theband can be used, including overlapping and welding, soldering, andmechanical interlocking as by folding together, bending together,twisting and affixin-g cleats or other fastening devices.

These ends 35 are bent in the circumferential direction as shown at 40in FIGURE 3, a convenient way being by hitting the ends with a hammer orby using a similar motion of a die.

Thus it will be seen that the finished insulator as shown in FIGURE 3has a portion of its outer circumference formed by each one of theinsulator segments.

In some cases it is preferable to form threads or gripping surfaces 41(hereinafter called corrugations) on the faces of the recesses 24 of theinsulator segments as shown in FIGURE 3a, in order to more effectivelyguard against the possibility of slippage of the resistor coils throughthe insulator. If it is desired, the gripping surfaces may extendentirely across the surface of the nose and the recesses at each side asshown in FIGURE 3b at 41'.

It is important that the band be tight. If difficulty is encountered inmaintaining the band tight by the particular fastening means used, theband can be further tightened as shown in FIGURE 3c by forming inwardbends or indentations in the band at 39 opposite the gaps between theinsulators, as by moving radially inwardly die projections 39, using amechanism for example similar to the means for manipulating the chucksas in FIGURE 6. The effectiveness of the indentations in maintainingtightness will be increased by using a band which is relatively stilf,as for example, a fairly stilf wire.

As shown in FIGURE 5 the resistor coils can be fed from spools not shownthrough a guide trough 45 and guiding eyes 46 so that the resistorsdescend vertically as shown at 47 into the chuck 28 in FIGURE 5.

As shown in FIGURE 6 the chuck consists of a housing 48 sliding onvertical guides 50 under the action of a double acting cylinder andpiston combination 51 anchored at one end on an abutment 52 and securedto the chuck housing 48 at the other end. Each chuck jaw 27 ispreferably energized to move it in and out by a double acting fluidpiston and cylinder combination 53, it being evident, of course, thatfluid is admitted and discharged from each end of each cylinder byvalves.

FIGURE 7 shows conveniently the operation of the cylinders, withoutconcern with the well known features of the valve mechanism. As shown,the operation of the advance cylinder is indicated by curve 54 and theoperation of the chuck cylinders is shown by curve 55. At a givenstarting point the advance cylinder is retracted as suggested by line56, and the chuck is, of course, in its uppermost position. The chuckcylinders are operating to hold the chuck open as shown by line 57 onthe curve 55. When the insulator segments and the band are properly inplace in the chuck with respect to the resistors, the chuck closes asshown by line 58 of curve 55, the closed position being suggested byline 60. Then the band is welded and the ends of the band are bent backout of the way. After the chuck is closed and the welding is complete,the advance cylinder advances as indicated by line 61 on curve 56, theadvance position of the advance cylinder being shown by line 62. Then assuggested by line 63 on curve the chuck cylinders open the cuhck and asshown by line 64 on curve 54 the advance cylinder is then retracted,moving the chuck back, the spring fingers 31 yielding to allow the chuckto pass over the forwardly positioned insulator segments without pullingthe entire heater back from its forward position. If friction is notsufficient to hold the insulator in forward position, a ratchet andpawl, not shown, may be used as well known in the art.

It will be evident that the fluid means on the chuck must permitregulation of its pressure or its pressure must be regulated by springsas well known in the chuck art.

Of course, the distance between centers of insulators can be varied inthe forms shown, it being of the order of 2 inches or 2 /2 inches in thepreferred form, so that there is a considerable length of resistorsbetween insulators to provide for flexibility in all directions.

The combination of insulators and resistors making up the heater canconveniently be changed to a horizontal direction by elbow 65 and thenthe heater can be directly fed into a flexible hose or pipe as desiredat 66. If preferred, the combination of the resistors and insulators canbe shipped to the point of installation as a roll or coil.

Thus it will be evident that in the form of FIGURES l to 7 the resistorsare preferably fed vertically and the insulator segments are assembledon them and held in place by the band on a vertical axis and byautomatic or semiautomatic operation.

In some cases it may be preferable to assemble the componentshorizontally, using a troughlike jig as shown in FIGURES 8 to 12inclusive.

In this case the resistors 20 are fed suitably in equallycircumferentially displaced position horizontally through the length ofthe jig 70, which is provided with a bottom 71, boxlike side walls 72and at suitable places along the length notches 73 in the side walls forreceipt of the insulator segments.

In FIGURE 9 the resistors are eliminated for clarity of illustration andin FIGURE 10 one of the resistors is eliminated for this purpose.

At a point opposite the notches 73 the side walls have near the topnotches 74 and receive a U-shaped band, in this case a wire 25', theopen part of the U being disposed upwardly. The bottom of the U rests onthe bottom 71 of the jig and the band extends through the side notches73 as best seen in FIGURE 9. A bottom insulator segment 21 is rested onthe bottom as shown in FIGURES 8 and 9 with the tongue 23 central ondupstanding, the band extending'through a groove 30' in the outsidecircumference of the insulator segment.

As shown in FIGURE 10, the resistors are rested in the recesses 24 oneither side of the tongue 23 of the upwardly disposed insulator segment21. They are restrained from movement outwand by shoulders 75 in theside walls.

In the next step as shown in FIGURE 11 at the next insulator position,insulator segments 21 are disposed at each side with the tongues 23directed downward and the lower recesses 24 resting on the top andoutside portions of the resistors 20. The bottom portions of thesidetmost insulator segments are engaged and supported by the walls ofthe notches 73 and the circumferential grooves 30' in the outsides ofthe insulator segments are in line with the band As shown in FIGURE 11,pins 76 in the center of the jig support the center upper resistor.

As shown in FIGURE 12, the upper side insulator segments are pushedtoward one another and downward so that each one of the resistors isfirmly gripped between opposed sides of insulator segments and pinchedradially inward so that it is no longer free to move longitudinally, andband 25 is joined by twisting at 38' so as to tightly hug the insulatorsegments and confine them as shown in FIGURE 12.

The previous forms show desirable means and processes for assemblinginsulator segments on three resistors.

In FIGURE 13 I show a construction for positioning six resistors 20 ateach of the insulator locations. In this form a suitably generallyhexagonal insulator core 80 has at what would othenwise be each hexagoncorner a recess 24' for receiving a resistor.

Insulator segments 21 each having opposed legs 81 bent at an anglecorresponding to the corner angle and intermediate resistor receivingrecesses 24 are positioned at points to engage and radially contracteach of the coiled resistors against its resilient tendency to radiallyexpand, thus gripping the resistor against longitudinal motion. Each ofthe insulator segments has around the outside circumference a groove 25which receives a band and when the segments are tightend to grip theresistors against the insulator core the ends of the band are joined asby twisting at 38'.

It will be understood that the form shown in FIGURE 13 can be modifiedto accommodate other numbers of resistors greater than three, forexample, four, six, eight or nine.

FIGURE 13a shows a modification of the fiorm of FIGURE 13, in which theinner core 80' has a series of axially extending outer recesses 24 inthis case six, and each insulator segment 21 brings pressure inwardly ontwo resistors 20 by virtue of the band 30, which extends around a recessin the outer circumference of the insulators. Each of the insulators hastwo recesses 24 and an intervening tongue portion 23.

If an insulator segment breaks, then the band 30 can be cut, and areplacement segment inserted and a new band fastened in place.

For many circuit arrangements the electric feeding connections will beall at one end and suitable jumpers or cross connections will be appliedat the far end.

In the case of three-phase star connection or single phase with a spareresistor, it is important to be able to cross connect the threeconductors at the end remote from the end where the power is fed.

In FIGURES l4 and 15 jumper portions 82 are bent from the end of eachresistor and joined at 83 and the joint is protected as by a screw-oninsulator cap 84 shown in FIGURE 14.

In FIGURE 16 a special end insulator 85 is provided with openings 86 forthe jumper portions 82 of the resistors, the endmost portion of theinsulator 85 having three radially converging grooves 87 which are deepenough to receive and insulate the twisted joint 83 common to the threeresistors. The jumper portions themselves hold the endmost insulator 85in place.

It will be understood, of course, other connections can be used asdesired. For example, in a three-phase circuit the connections may bestar or delta, and any suitable arrangement may be used for othernumbers of phases.

In view of my invention and disclosure, variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art to obtain all or part of the benefits of myinvention without copying the structure, mechanism and process shown,and I, therefore, claim all such insofar as they fall within thereasonable spirit and scope of my claims.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. In an electric heater, three parallel helical metallic electricresistors which are resilient radially and laterally, the resistorsbeing equally circumferentially spaced from one another, a plurality oflongitudinally spaced ceramic insulators, each of which is composed ofthree insulator segments, each insulator segment having a projectingtongue extending radially inward between two resistors, having alongitudinal groove in each of two opposite sides of the tongue providedwith corrugations which receive and grip one of the helical resistorsand radially compresses the resistor against its radial resilience, theinsulator segments having an external annular groove, and band means inthe groove holding the insulator segments in gripping engagement withthe helical resistors.

2. In an electric heater, more than three parallel helical metallicelectric resistors which are resilient radially and laterally, theresistors being equally circumferentially spaced from one another, aplurality of longitudinally spaced ceramic insulators, each of which hasat least three insulator segments and an insulating core portion whichis radially within the resistors and has a longitudinally outwardlydisposed groove engaging the inside of each resistor, each insulatorsegment engaging the outside of a resistor, there being on the engagingsurfaces of the insulator segments and the core portion corrugationswhich grip the resistors to radially compress the resistors againsttheir radial resilience, the insulator segments having an externalannular groove, and band means in the groove holding the insulatorsegments in gripping engagement with the helical resistors.

3. In an electric heater, six parallel helical metallic electricalresistors which are resilient radially and laterally, the resistorsbeing equally circumferentially spaced from one another, a plurality oflongitudinally spaced ceramic insulators, each of which is composed ofat least three insulator segments and having an insulating core portionwhich is radially within the resistors and has a longitudinal outwardlydisposed groove provided with corrugations which engage the inside ofeach resistor, each insulator segment engaging the outside of a resistorand having corrugations which grip it against the insulator core portionand radially compress the resistor against its radial resilience, theinsulator segments having an 7 8 external annular groove, and band meansin the groove 2,515,603 7/1950 Kaplan 174-155 holding the insulatorsegments in gripping engagement 2,639,312 5/1953 Kerwin 174-88 X withthe helical resistor. 2,790,889 4/ 1957 Hynes 219--539 X 2,963,53912/1960 Hynes 174-138 References Cited 3,045,097 7/ 1962 Sellers L219-552 X UNITED STATES PATENTS 3,286,078 11/1966 Hynes l 219-306275,425 4/1883 Shelbourne 174-99 VOLODYMYR Y. MAYEWSKY, PrimaryExaminer. 354,892 12/1886 Du Bois 174-99 US Cl XR 873,456 12/1907Ottinger 174--155 X 1,013,241 1/1912 Van Etten 174-155 1017499,155;219550

